User FMN-Music has been more on top of this issue. One pretty weird behaviour he noticed is turning the plugins in the bus that receives the sidechain signal off and then on makes at least some of the PDC problems go away. Maybe try that before bouncing. I've reported the issue twice to support, I think @FMN-Music has done it too and I think I read somewhere that the dev team is aware and working on it but it's taking quite a while. These are pretty serious bugs in a DAW IMHO...
Thanks! It seems to work to bounce all the source channels feeding the side chain busses so that there are no plugins on them. However since you always want add and exchange/tweak plugins during mixing this is not really a viable solution in day-to-day work.
I agree. This one is just as urgent as the "automation missing during export" bug in 8.0.0. and deserves a hot fix as well.